We are investigating the effects of estrogens on human uterine tissue in vitro with particular reference to estrogen binding and protein biosynthetic activity in premenopausal specimens as a function of stage of the cycle, and also in postmenopausal and cancerous uterine tissues and cells. BIBLIOGRAPHIC REFERENCES: Schmidt, W.N., Sadler, M.A., and Katzellenbogen, B.S. Androgen-uterine interaction: Nuclear translocation of the estrogen receptor and induction of the synthesis of the uterine induced protein (IP) by high concentrations of androgens in vitro but not in vivo. Endocrinology 98:666-680 (March 1976, in press). Gannon, F., Katzenellenbogen, B.S., Stancel, G., and Gorski, J. Estrogen receptor movement to the nucleus: Discussion of a cytoplasmic exclusion hypothesis. In: The Molecular Biology of Hormone Action, J. Papaconstantinou (Ed.), in press (1976).